This invention relates to gas generators for converting a reaction mixture consisting of atomized, vaporized or evaporated liquid, hydrocarbon fuel and a gas containing oxygen into a fuel gas at elevated temperature and more particularly to a gas generator which obtain more uniform heating and can thus be more heavily loaded.
In what are known as reformed gas generators, atomized, vaporized or evaporated liquid hydrocarbon fuel is reacted with a gas containing oxygen, for instance, air or exhaust gas, and is converted at elevated temperature into a fuel gas (reformed gas) containing carbon monoxide, methane and/or hydrogen. This fuel gas can be mixed, for instance, with combustion air and fed to an internal combustion engine. While in internal combustion engines fed with liquid fuel, as in motor vehicles, an incomplete vaporization of the fuel and the nonuniform mixing with combustion air leads to incomplete combustion and emission of harmful substances, the reformed gas is burned largely without residue. Furthermore, since it has a high octane number, the addition of antiknock media can be dispensed with, so that the content of substances detrimental to health in the exhaust gas of the internal combustion engines is lowered.
German Pat. No. 482,157 teaches a method in which hydrocarbon fuel is processed with air in a gas generator for feeding to an internal combustion engine. The gas generator contains several parallel tubes of catalytically active metal which are accommodated in a housing. The fuel/air mixture can be conducted through the tubes which act as the reaction chamber and are heated by exhaust gas flowing through the housing, or the exhaust gas can be conducted through the tubes and the reaction mixture through the housing. The reaction chamber may also contain metal filings or other catalytically active packing materials. Ribs or other profiled parts may be attached to the tubes for improving the heat transfer. The reaction chamber may also be heated electrically instead of with exhaust gas and catalytical metal fabric, wires, balls or plates may also be provided instead of the catalyzer tubes.
Capacity increases over such reactors, i.e., a high degree of conversion of the liquid fuel used even with high fuel throughout is provided by the reformed gas generator described in U.S. Pat. No. 3,828,736. In the gas generator disclosed therein, several spaced plates of porous ceramic material, which are impregnated with a catalytic metal component and are provided with a multiplicity of passage openings, are arranged in tandem in the reaction chamber. Such catalyzer plates have a large specific surface and at the same time have a small catalyst volume. The spaces between the plates serve as mixing chambers for the reformed gas generated at the preceding plate and for the part of the reaction mixture which has not yet reacted and which is being fed to the pores of the subsequent plate. In order to maintain the elevated reaction temperature at the catalyzer plates, the reaction chamber is also heated from the outside by the hot exhaust gas of the internal combustion engine connected to the reformed gas generator.
Stabilization of the flow in a reformed gas generator containing catalysts by letting a temperature resistant body having flow canals precede the catalysts has been proposed. By doing so, the flow of the reaction mixture against the catalysts is always laminar and no turbulence develops in the spaces between the catalysts, which turbulence could lead to the formation of flames. The temperature resistant plates for this purpose preferably are plates of ceramic material, e.g., ceramic alumina-silicate fibers, with flow canals punched therethrough.